[Python-checkins] r77483 - python/trunk/Python/dtoa.c
mark.dickinson
python-checkins at python.org
Wed Jan 13 23:20:10 CET 2010
Author: mark.dickinson
Date: Wed Jan 13 23:20:10 2010
New Revision: 77483
Log:
More dtoa.c cleanup; remove the need for bc.dplen, bc.dp0 and bc.dp1.
Modified:
python/trunk/Python/dtoa.c
Modified: python/trunk/Python/dtoa.c
==============================================================================
--- python/trunk/Python/dtoa.c (original)
+++ python/trunk/Python/dtoa.c Wed Jan 13 23:20:10 2010
@@ -270,7 +270,7 @@
typedef struct BCinfo BCinfo;
struct
BCinfo {
- int dp0, dp1, dplen, dsign, e0, nd, nd0, scale;
+ int dsign, e0, nd, nd0, scale;
};
#define FFFFFFFF 0xffffffffUL
@@ -437,7 +437,7 @@
NULL on failure. */
static Bigint *
-s2b(const char *s, int nd0, int nd, ULong y9, int dplen)
+s2b(const char *s, int nd0, int nd, ULong y9)
{
Bigint *b;
int i, k;
@@ -451,18 +451,16 @@
b->x[0] = y9;
b->wds = 1;
- i = 9;
- if (9 < nd0) {
- s += 9;
- do {
- b = multadd(b, 10, *s++ - '0');
- if (b == NULL)
- return NULL;
- } while(++i < nd0);
- s += dplen;
+ if (nd <= 9)
+ return b;
+
+ s += 9;
+ for (i = 9; i < nd0; i++) {
+ b = multadd(b, 10, *s++ - '0');
+ if (b == NULL)
+ return NULL;
}
- else
- s += dplen + 9;
+ s++;
for(; i < nd; i++) {
b = multadd(b, 10, *s++ - '0');
if (b == NULL)
@@ -1180,26 +1178,14 @@
bc is a struct containing information gathered during the parsing and
estimation steps of _Py_dg_strtod. Description of fields follows:
- bc->dp0 gives the position of the decimal point in the input string
- (if any), relative to the start of s0. If there's no decimal
- point, it points to one past the last significant digit.
-
- bc->dp1 gives the position immediately following the decimal point in
- the input string, relative to the start of s0. If there's no
- decimal point, it points to one past the last significant digit.
-
- bc->dplen gives the length of the decimal separator. In the current
- implementation, which only allows '.' as a decimal separator, it's
- 1 if a separator is present in the significant digits of s0, and 0
- otherwise.
-
bc->dsign is 1 if rv < decimal value, 0 if rv >= decimal value. In
normal use, it should almost always be 1 when bigcomp is entered.
bc->e0 gives the exponent of the input value, such that dv = (integer
given by the bd->nd digits of s0) * 10**e0
- bc->nd gives the total number of significant digits of s0.
+ bc->nd gives the total number of significant digits of s0. It will
+ be at least 1.
bc->nd0 gives the number of significant digits of s0 before the
decimal separator. If there's no decimal separator, bc->nd0 ==
@@ -1218,13 +1204,14 @@
bigcomp(U *rv, const char *s0, BCinfo *bc)
{
Bigint *b, *d;
- int b2, bbits, d2, dd, dig, i, j, nd, nd0, p2, p5;
+ int b2, bbits, d2, dd, i, nd, nd0, p2, p5;
+ dd = 0; /* silence compiler warning about possibly unused variable */
nd = bc->nd;
nd0 = bc->nd0;
p5 = nd + bc->e0;
- if (rv->d == 0.) { /* special case: value near underflow-to-zero */
- /* threshold was rounded to zero */
+ if (rv->d == 0.) {
+ /* special case because d2b doesn't handle 0.0 */
b = i2b(0);
if (b == NULL)
return -1;
@@ -1243,9 +1230,8 @@
that b << i has at most P significant bits and p2 - i >= Emin - P +
1. */
i = P - bbits;
- j = p2 - (Emin - P + 1);
- if (i > j)
- i = j;
+ if (i > p2 - (Emin - P + 1))
+ i = p2 - (Emin - P + 1);
/* increment i so that we shift b by an extra bit; then or-ing a 1 into
the lsb of b gives us rv/2^(bc->scale) + 0.5ulp. */
b = lshift(b, ++i);
@@ -1300,55 +1286,43 @@
}
}
- /* Now 10*b/d = exactly half-way between the two floating-point values
- on either side of the input string. If b >= d, round down. */
+ /* if b >= d, round down */
if (cmp(b, d) >= 0) {
dd = -1;
goto ret;
}
- /* Compute first digit of 10*b/d. */
- b = multadd(b, 10, 0);
- if (b == NULL) {
- Bfree(d);
- return -1;
- }
- dig = quorem(b, d);
- assert(dig < 10);
-
/* Compare b/d with s0 */
-
- assert(nd > 0);
- dd = 9999; /* silence gcc compiler warning */
- for(i = 0; i < nd0; ) {
- if ((dd = s0[i++] - '0' - dig))
+ for(i = 0; i < nd0; i++) {
+ b = multadd(b, 10, 0);
+ if (b == NULL) {
+ Bfree(d);
+ return -1;
+ }
+ dd = *s0++ - '0' - quorem(b, d);
+ if (dd)
goto ret;
if (!b->x[0] && b->wds == 1) {
if (i < nd)
dd = 1;
goto ret;
}
+ }
+ s0++;
+ for(; i < nd; i++) {
b = multadd(b, 10, 0);
if (b == NULL) {
Bfree(d);
return -1;
}
- dig = quorem(b,d);
- }
- for(j = bc->dp1; i++ < nd;) {
- if ((dd = s0[j++] - '0' - dig))
+ dd = *s0++ - '0' - quorem(b, d);
+ if (dd)
goto ret;
if (!b->x[0] && b->wds == 1) {
if (i < nd)
dd = 1;
goto ret;
}
- b = multadd(b, 10, 0);
- if (b == NULL) {
- Bfree(d);
- return -1;
- }
- dig = quorem(b,d);
}
if (b->x[0] || b->wds > 1)
dd = -1;
@@ -1369,7 +1343,7 @@
double
_Py_dg_strtod(const char *s00, char **se)
{
- int bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, e, e1, error;
+ int bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, dp0, dp1, dplen, e, e1, error;
int esign, i, j, k, nd, nd0, nf, nz, nz0, sign;
const char *s, *s0, *s1;
double aadj, aadj1;
@@ -1378,7 +1352,7 @@
BCinfo bc;
Bigint *bb, *bb1, *bd, *bd0, *bs, *delta;
- sign = nz0 = nz = bc.dplen = 0;
+ sign = nz0 = nz = dplen = 0;
dval(&rv) = 0.;
for(s = s00;;s++) switch(*s) {
case '-':
@@ -1417,11 +1391,11 @@
else if (nd < 16)
z = 10*z + c - '0';
nd0 = nd;
- bc.dp0 = bc.dp1 = s - s0;
+ dp0 = dp1 = s - s0;
if (c == '.') {
c = *++s;
- bc.dp1 = s - s0;
- bc.dplen = bc.dp1 - bc.dp0;
+ dp1 = s - s0;
+ dplen = 1;
if (!nd) {
for(; c == '0'; c = *++s)
nz++;
@@ -1624,10 +1598,10 @@
/* in IEEE arithmetic. */
i = j = 18;
if (i > nd0)
- j += bc.dplen;
+ j += dplen;
for(;;) {
- if (--j <= bc.dp1 && j >= bc.dp0)
- j = bc.dp0 - 1;
+ if (--j <= dp1 && j >= dp0)
+ j = dp0 - 1;
if (s0[j] != '0')
break;
--i;
@@ -1640,11 +1614,11 @@
y = 0;
for(i = 0; i < nd0; ++i)
y = 10*y + s0[i] - '0';
- for(j = bc.dp1; i < nd; ++i)
+ for(j = dp1; i < nd; ++i)
y = 10*y + s0[j++] - '0';
}
}
- bd0 = s2b(s0, nd0, nd, y, bc.dplen);
+ bd0 = s2b(s0, nd0, nd, y);
if (bd0 == NULL)
goto failed_malloc;
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